1. Field of the Invention
The present invention relates to a cartridge which is detachably attached to a main body of an electrophotographic image forming apparatus.
The electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming process. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (such as a laser beam printer and an LED printer), a facsimile machine and a word processor.
The cartridge may be, for example, a process cartridge, a development cartridge or a toner cartridge, which is detachably attached to a main body of an electrophotographic image forming apparatus and contributes to an image forming process to form an image on a recording medium.
The process cartridge is a cartridge which includes a development portion as a process portion and a photosensitive drum, which are integrated to form a cartridge, and is detachably attached to a main body of an electrophotographic image forming apparatus. Thus, a cartridge which includes one of a charging portion, cleaning portion and the development portion as a process portion, and the electrophotographic photosensitive drum, which are integrated to form a cartridge and is detachably attached to the main body is also one of process cartridges. A process cartridge integrally including an electrophotographic photosensitive drum and a development portion is referred to as a so-called integrated type cartridge. A process cartridge integrally including an electrophotographic photosensitive drum and a process portion other than the development portion is referred to as a so-called separated type cartridge.
The process cartridge can be attached to and detached from an image forming apparatus main body by a user. Therefore, maintenance of the apparatus main body can be performed easily. The process portion operates on the electrophotographic photosensitive drum.
The development cartridge also includes a development roller, which accommodates a developer (toner) used to develop an electrostatic image formed on the electrophotographic photosensitive drum, and is detachably attached to the main body. In the case of the development cartridge, the electrophotographic photosensitive drum is mounted on the apparatus main body. Alternatively, the electrophotographic photosensitive drum is arranged in the so-called separated type process cartridge (in this case, the process cartridge does not include the development portion). The development cartridge can also be attached to and detached from an image forming apparatus main body by a user. Therefore, maintenance of the apparatus main body can be performed easily.
The toner cartridge is a cartridge which accommodates a developer (toner), has an opening through which the developer is fed and which is unsealably sealed by a sealing member, and is detachably attached to the main body. The toner cartridge can also be attached to and detached from an image forming apparatus main body by a user. Therefore, maintenance of the apparatus main body can be performed easily.
2. Description of the Related Art
In the related art, an image forming apparatus using an electrophotographic image forming process employs a process cartridge system in which a photosensitive drum and a process portion operating thereon are integrated to form a cartridge, and the cartridge is detachably attachable to a main body of the image forming apparatus. In such a process cartridge, an opening formed in a developer frame member which accommodates a developer (toner) is sealed with a sealing member and the opening is unsealed by pulling the sealing member out in use to enable feeding of the developer.
A method of thermally welding a sheet-like sealing member 52, which has an adhesion layer such as a heat sealing portion 53, to a periphery of an opening of a developer frame member 51 as illustrated in FIG. 6 is known as a method for unsealably sealing an opening, as disclosed in Japanese Patent Application Laid-Open No. 2006-208898. This method is widely used with a structure in which a free end of the sealing member 52 is folded back and the heat sealing portion (welding portion) 53 is easily separated by pulling out the sealing member 52 in the direction opposite to the folded back portion (in the direction of an arrow J in FIG. 6) so as to reduce the load on the user when pulling out the sealing member.
However, in the above example of the related art, since the sealing member is provided with the adhesion layer to thermally weld the sealing member to the periphery of the opening, the structure of the sealing member is complex. Moreover, since the sealing member is folded back in view of the load to separate the welding portion when pulling out the sealing member, the length of the sealing member in the pulling direction is long (about twice as long as the portion which seals in the developer), and consequently, the pulling amount of the sealing member when unsealing the opening is large.